* Fixed non-circular curve orientation handling
* Section changed to use Part::CrossSection, because it seems
BRepAlgoAPI_Section has trouble with non-circular curves (LastParameter
becomes huge which causes discretization to produce many many points)
* Exposed Area.makeSections() to section with variable heights
* Modified Area.setPlane() to accept non-planar shape
* Exposed Area.getPlane() to obtain current workplane
* Exposed Area.Shapes attribute to return the current holding children
shape.
* Path.fromShapes can now convert any number of shapes to Path with
optimzied travel distances. It internally uses Path.sortWires to
minimize travel distances, and also sort wires by its Z height in case
of sectioned wires.
* The above python function is impelmented in Path::Area class.
* Path::FeatureShape is rewrote to take advantage of these two
functions.
* Add Path::FeatureAreaView to partially display a Path::FeatureArea's
sections.
